Development of a movable and simplified jujube separator

Abstract: 【Objective】Xinjiang is one of the main producing areas of jujube in China, which is more distinctive in southern Xinjiang because of its special climate. However, at present most of the jujube harvest in southern Xinjiang is mainly completed by artificial picking, with low efficiency, high cost and time consuming. Although some research institutions and enterprises have developed many machines and tools to try mechanized harvesting, the practical application effect is still unsatisfactory; and therefore, artificial harvesting will continue to exist for a long time. There are two main ways for the artificial jujube harvesting: one is cherry-picking operation and the other is picking up operation by sweeping. The cherry-picking operation can get clean red dates easily but the operation efficiency is low; and the picking up operation by sweeping can get high efficiency and good effect, but with a higher rate of impurity. And now the artificial collecting by sweeping method has been improved with relatively high efficiency and good effect, so that it has been applied increasingly. Unfortunately, the pickedup jujube by sweeping contains much impurity, such as leaves, small branches, broken soil, sand and other debris that need to be removed. Now the simple screen mesh is used with low efficiency and undesirable effect. There are no specialized impurity removal tools available currently so that it is urgent to develop a suitable and portable impurity removal equipment to improve the situation. Therefore, the main purpose of this study is to solve the problem of removing the impurity in the process of picking up thjujube. Specifically, according to the operation characteristics of picking up jujube and the impurity situation, a special equipment for removing impurity from the jujube was developed. The machine can solve the problem, and obtain a higher pick-up efficiency, better effect and lower cost. For this purpose, this study will analyze the component composition of mixed jujube, the size of the date and the impurity situation. Also it includes the determination of the overall machine plan and the designing of key components. At the same time, the preliminary prototype processing and field experiment were carried out.【Methods】Based on the mechanical design theory and method, as well as the existing planting patterns and the status in relation to jujube harvest operation in southern Xinjiang, the present study was undertaken in Xinjiang as a research project. For picking up the dry jujube leaves, floating soil, dust and other light impurities, the wind blowing was used to remove light impurities. As for the heavy impurities such as the branches, clods and pebbles, the impurities were removed by using the screen sorting, which determined the overall scheme of the jujube separator machine. The machine was made up of rack, unloading mechanism, screening plant, power plant, centrifugal fan, collection basket, road wheel and some other parts. The specific working principle is as follows: when it starts working, the mixed dates fall and are spread to the smooth screen plate through the cone hopper under gravity, and continue to slide. When the mixed dates pass through the lower end of the composite screen, the blower driven by the gasoline engine directly blows the falling materials, and blows away the leaves, dust and other light impurities into the light impurity settling chamber. In the settling chamber, the light impurities slide down the side wall into the light impurity collection basket due to the sudden weakening of the wind and the effect of gravity. Simultaneously, when the dates with heavy impurities roll across the composite screen, the impurities like small stones and soil lumps fall into the heavy impurity collection basket, and finally the clean dates fall into the jujube collection basket, and the field impurity removal operation is finished. At the same time, according to the sample parameters of jujube with impurity, the hopper-screen and the impurity removal screen were designed. Based on the average mass and shape of the jujube, the centrifugal blower was designed and selected. The small gasoline engine was matched and selected according to the power of the centrifugal blower, and according to the general design plan and detailed design requirements, we finally contacted the related agricultural machinery department for manufacturingthe sample machine.【Results】According to the overall design scheme, the sample jujube separator machine was trial-produced. The basic performance of the machine was confirmed by field test which showed that the overall impurity removal effect was good with higher efficiency and therewere basically no dried leaves in the dates after the operation. Generally speaking, the performance of the machine has reached the expected design goal. The removal rate of the prototype was 87.6%, the loss rate was 2.3%, and the productivity was 306 kg·h-1. Compared with manual picking, the removal efficiency was about 5 times higher.【Conclusion】The development of the jujube separator machine provided an auxiliary operating equipment, which can improve the efficiency and reduce the labor intensity.The basic performance of the machine was confirmed through field test, providing a reference for further optimization and improvement of the machine. The research and development of this machine was mainly to solve the problem that there was no special auxiliary machine in the process of the picking up operation by sweeping. It is a transitional auxiliary machine, but has not fundamentally solved the problem of artificial picking up jujube. However, it can relatively increase artificial pickup efficiency, improve operation effect and reduce pickup cost, thus having certain market application prospect. At the same time, for the current difficulties encountered in the jujube harvest, the development of this machine also provides a way for the development of the jujube combine harvester.